All conventional treatment systems require an effluent collecting station of which solid particles are sediment, and the entire waste water is passed through a 25 mm screen to remove coarse, solid material. A comminutor may be applied to shed coarse materials before screening the effluent. The collection station may typically be equipped with an overflow to prevent flooding. From the effluent collection station, the waste water may be transferred to a balancing tank or directly to secondary treatment.
There is a need for a low maintenance treatment plant which provides a high degree of purification at a low energy cost and a low capital cost. Furthermore the design should be compact making it relatively easy to install with minimum disturbance to the landscape. Ideally the plant should operate without any treatment of sludge required, or produce a relatively low amount of sludge.